Learn me- 1984 corvettes

wheels777 wrote:

Ovid_and_Flem wrote: In reply to wheels777: Aren't there some NHRA regs that affect IRS cars that get down into the 10s or 11s?

There are regs. It will be a weekend and Friday night special. If it were to go to the Challenge, it will be a fun fast car...but not the quickest.

Well, mr. Nelson, you've dominated the drag racing Challenge and you dominated the Concours challenge so you might as well make it a trifecta and show up with a car that handles and dominate the autocross. Deservedly so I might add

If your 96 manual trans car is a modded LT1 instead of an LT4, either the engine or the trans was not always mated to the other and has been swapped. Doesn't make it a bad car, though.

all things considered(I am familier with a couple of 'em)(lt4's) an lt1 is a good choice. P.S.if you show up with an lt4 I will protest or request a Claimer rule. But what the Hey it' wouldn't be the First Boat Motor to Grace the pages of GRM.. just the challenge.....so OK but it WAS in this Forum. the Volvo W/ an evenrude or something

GTXVette wrote: all things considered(I am familier with a couple of 'em)(lt4's) an lt1 is a good choice. P.S.if you show up with an lt4 I will protest or request a Claimer rule. But what the Hey it' wouldn't be the First Boat Motor to Grace the pages of GRM.. just the challenge.....so OK but it WAS in this Forum.

Just Kidding I'm Bringing plenty

In reply to GTXVette:

Says the guy who has a 650 HP 454 Big Block mounted 14 inches rearward in a C4 Corvette

BUT IT'S A BOAT MOTOR!!!!!!!!!!!!!! oop's.

and I got a Laywer.

GTXVette wrote: BUT IT'S A BOAT MOTOR!!!!!!!!!!!!!! oop's. and I got a Laywer.

Well, yeah, but it's in a fiberglass vehicle. Aaren't aren't boats fiberglass ?

here is how I see It. I am Barely Making 1.3 HP per Cube,Japs are Laughing At that as LOTS of them Make 1.9 to 2.1 HP per Cube.

And as to that about where it sits, Well I had to Put it Somewhere.

And Mericans laugh at Japanese "torque."

It's all relative.

Ovid_and_Flem wrote:

GTXVette wrote: BUT IT'S A BOAT MOTOR!!!!!!!!!!!!!! oop's. and I got a Laywer.

Well, yeah, but it's in a fiberglass vehicle. Aaren't aren't boats fiberglass ?

If boats are for Fishin',and vettes are Stingrays or Sharks I must be the CLOWN FISH

Appleseed: 'ZAXLY what I was Thinkin'

In reply to Trackmouse:

My 86 had a problem with the transmission. That 4+3 arrangement is weak and the syncro's can be worn out in less than 50,000 miles.. The instrument panel is a nightmare to work on and expensive to have worked on.. A carbed intake manifold for one is different because of the intake ports in the heads.. and the fuel injection pump is high pressure so you will need to change the fuel tank to accept a low pressure pump

We need a GRM C4 registry. There is little doubt that they are going to jump up in the future and are a bargain today. C5s won't drop to the C4 price levels. C3s continue to rise.

What's the deal with that 4+3 transmission? It's a four speed with over drives for 2,3,&4?

In reply to Trackmouse:

Yes. There was an overdrive unit just like some 3-speeds had in the 50s, or MGBs and Volvos had in the 70s/80s. I forget about the Volvo (even though I drove one for a little while a year or two ago, thanks Evan!) but the MGB unit had a manual switch on the shifter and a lockout switch on the trans, so you could only engage the overdrive in 3rd or 4th gear. (I got to diagnose/repair/rebuild one last year. Fun times. Very English in its brute force engineering.)

Now, I have never even seen a 4+3 in the wild let alone driven one, but I understand that the overdrive was COMPUTER controlled and it would engage it in 2nd, 3rd, and 4th gear under the right conditions. Which, being 80s level of tech, were probably sometimes the wrong conditions. But at the time nobody made an overdrive trans that could handle the torque of a 350, so that's what Chevy used until they started using that ZF trans.

(NB: Driving that MGB for a half hour or so, shifting in an out of Overdrive over and over again to make sure it worked correctly, playing with the vacuum switch via throttle and the button on the dash, is most of the reason why I bought another RX-7, since I bought my FIRST RX-7 after wanting an MGB and being unable to find one in decent shape. And there's something clunky yet magic about a light, simple car with a simple, low powered carbureted engine.)

In reply to Knurled:

The 4+3 transmission is much-maligned... especially the later models which were more reliable. keep in mind you can switch off the overdrive function and drive it just like a regular 4-speed manual. Just push the shift pattern button on the shift knob after you start it. Automatically switches back to OD mode when you turn off engine. The ratios for OD are almost idenrical to the next gear upshift....that is 2ND OD is almost identical to 3Rd gear regular, 3Rd OD is almost idenrical to 4the regular and 4the od is a bit taller than 4the regular.

That being said they are expensive to repair if you want to keep the overdrive function.

What manual transmissions "swap right in"? (Since I'm a need on everything American)

Trackmouse wrote: What manual transmissions "swap right in"? (Since I'm a need on everything American)

700-R4 with a manual valve body and decent ratchet shifter.

There is no such thing as a decent manual trans in a C4, they all suck. As a bonus, something like 90% of C4s were automatic so this is also the easy button.

It's not like there's enough room in the footwell to work a clutch, anyway, unless you have hooves.

I somehow worked in a shop that saw a lot of Corvette traffic in the late 90s. We also were one of the few places in a 200 mile radius certified to work with the run-flats on C5s. The first time I drove a C5 after nothing but C3s and C4s cannot be described in words. Here was a car that not only didn't flex like a Wrangler with bad body mounts, but it had INTERIOR ROOM! It might as well have been from another planet, it certainly wasn't a Corvette-as-we-know-it.

In reply to Knurled:

^^^^ ++++100

Lightly modified auto works fine for drag racing and AX.....won't last more than a lap or 3 on road course due to heat generated. Footbox on manual cars is tight if you wear bigger than size 8 shoe.

I can't be the only guy to immediately troll Craigslist every time he checks in on this thread.

Not sure what there is to complain about with the ZF6. It has a rep for not liking high-torque applications but I haven't seen one break, just heard of it. The key to long life is they don't like to be hurried, so power shifting is a no-no. I'm not saying you're incorrect though, Knurled, you were a tech an I'm just a longtime owner and former autocrosser. You've probably seen a few things.

Anyway, auto is good for most applications and there is a factory cooler available for them if you're inclined. A cooler was standard on some automatic cars. O&F, you're right, it pays to select shoes carefully for manual trans cars, most athletic shoes have flares in the soles across the ball of the foot and they tend to hang on the pedals. I used to autox with a lady who wore ballet shoes in hers.

The 4+3 is a t-10 with an overdrive unit on the back. Strength is okay on the later boxes. There is or was a $200 rebuild kit for the OD at one time through the major Corvette retailers. This trans is in my 88 Callaway B2K and my biggest complaint is long throws. There used to be a kit to shorten throws on the factory shifter but no one seems to carry it any longer, I'd like to try it out sometime. I usually forget to disable the OD on startup until it engages on me once, haha. In the Callaway it's recommended to clutch the OD dis/engagements but not sure whether it's necessary in NA cars. The twin turbo makes monster torque.

Trackmouse wrote: What manual transmissions "swap right in"? (Since I'm a need on everything American)

If you really want a stick pick a strong trans that goes behind a SBC (Muncie, Super T-10, various dog clutch racing units, T-56, etc.) and build a bracket to tie it to the torque arm. Though at that point the smaller diff the automatic cars got probably becomes a weak point.

conesare2seconds wrote: Not sure what there is to complain about with the ZF6. It has a rep for not liking high-torque applications but I haven't seen one break, just heard of it. The key to long life is they don't like to be hurried, so power shifting is a no-no. I'm not saying you're incorrect though, Knurled, you were a tech an I'm just a longtime owner and former autocrosser. You've probably seen a few things.

If there is a weak link we will find it.

There are very good bolt-in options from TKO, but not on a Challenge-friendly budget.

Appleseed wrote: I can't be the only guy to immediately troll Craigslist every time he checks in on this thread.

Pretty regularly. I have my eye on the same three in my area. What year did they stop the 4+3? T found an '88 and it has that supposedly, but I thought the zf transmission started in '88.